17-Sep-2015

Well, the New York Times published a provocative opinion article Saturday by Timothy Snyder, likening the Holocaust to climate change and Nazi Germany to the U.S.* “Today we think of the Nazi Final Solution as some dark apex of high technology.” — wait, what? Huh? What do you mean we, kemosabe? What way is this an apex of high tech in any manner, however dark? If there was a “dark apex of high technology” used in that terrible war, it would be the atom bomb. Two paragraphs later the author writes “The quest for German domination was premised on the denial of science.”, as if he didn’t know that science denialism and high technology go together like oil and water. Oddly, after this cheap swipe at high tech at the start, in the second half of the article Tim Snyder seems to encourage technological contributions to the fight against greenhouse gas emissions.

Moving on… Fighting wars over farmland goes back to well before history began. As that is not new, what is riling up Mr. Snyder? Hygiene and modern (ie, evidence-based [ie, scientific]) medicine has led to population growth so that the carrying capacity of the land becomes a factor of much greater concern — when disease and misadventure limit the population moreso than famines, there is no point to plowing marginal farmland. If you want an authentically greater danger to be concerning yourself with, consider that antibiotic resistance threatens to erase what is perhaps the greatest contribution to the fight against disease by medical technology.

So, if it’s not about averting hunger, why has there been so much violence performed with the goal of securing farmland? Historically, it really was about hunger! A localized crop failure (caused by any of dozens of reasons, let’s say drought) lowers the carrying capacity of the farmed land, so there’s a famine, resulting in efforts to gain more farmland, but once the drought passes, the typical capacity of the old plus the new farmland becomes the new normal, and so when the lemmings swarm and decimate the crops you get a famine again, meaning you need more farmland, in a cycle every historian is depressingly familiar with. The old-school way out of this trap was to actually treat the “new” farmland as a buffer for dealing with shocks to the food supply, not as a normal part of how you feed the populace, and go bank the excess crop in a granary. The newer way out is to sell the excess crop because nowadays we have enormous wide-area food markets, and during lean times you go buy food from these markets you earlier sold to. Note that neither of these will handle a long-term, wide-area reduction in farm capacity, such as that caused by the Little Ice Age, and the climate change phenomenon we’re currently in could possibly become a crisis at least as severe.

Getting back to the main point of the NYT article, the observation that populations are increasing faster than farmed land of course isn’t news; it has been well known since being popularized by Thomas Malthus. So far, global Malthusian crises haven’t occurred because we’ve been turning more and more natural habitats previously considered non-arable into farms (due to advances in irrigation, etc.), and per-hectare farm productivity has been growing (pun intended) and Malthus didn’t foresee the Green Revolution. Whether productivity can (or more precisely, at what point can it no longer) continue to grow is a contentious question. Monsanto et al. insist that genetically engineered crops will be the Green Revolution II. Personally, I favor reducing our trophic level by getting more of our protein from beans and eating less meat — meat is phenomenally inefficient on a nutrients per hectare-year basis.

In theory, you can step off the treadmill of growing population requiring increasing food production by stabilizing your population and reaching a level of food production which can comfortably feed that population with an acceptable amount of farmed land at sustainable farm productivity levels. Then you get to sit back and say “problem solved!” without having to get more land to till or handing control of your agriculture to Monsanto Inc. — at least until climate change goes and torpedoes your farms’ productivity.

So yeah, let’s get on fixing that greenhouse gas emission thing, like right now. But it’ll happen much better if we make use of technology instead of trying to fight the advance of tech. When you have the options of “using tech” and “fighting tech”, the former has always worked out better than the latter. That will still hold true when it comes to the matter of climate change’s impact on global agriculture.

* Quoting verbatim: “Hitler spread ecological panic by claiming that only land would bring Germany security and by denying the science that promised alternatives to war. By polluting the atmosphere with greenhouse gases, the United States has done more than any other nation to bring about the next ecological panic…” There’s more in the article.

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18-Aug-2012

If you’ve been following along, you know that over the last several years advances in hydraulic shale fracturing (“fracking”) technology have opened up large new sources of natural gas to the energy production market. The Law of Supply being what it is, this has driven down the price of natural gas, and consequently electricity generation companies have switched from preferentially burning coal to preferentially burning natural gas, as that’s now the cheaper way to get a therm. The unexpected result of this is that the United States’s CO2 emissions from electricity generation have significantly dropped.

This is surprising at first. Why does switching from coal to natural gas reduce emissions so much? After all, they’re both fossil fuels. Well, coal is polycrystalline graphite with impurities, i.e., energetically essentially all carbon. To burn graphite, you put in energy to break C-C bonds then get energy when you form C-O bonds, and your only byproduct is CO2. Natural gas is primarialy methane, with other hydrocarbons and impurities. To burn methane you break C-H bonds, which are weaker than C-C bonds, and get energy from not only C-O bonds but also the stronger O-H bonds, so methane is a more efficient fuel. On top of that, much of your byproduct is water vapor, which doesn’t contribute to global warming.

Some numbers: Burning 1 mol of either graphite or methane produces 1 mol of CO2. Graphite’s molar heat of combustion is 393.5 kJ, while methane’s is 802.3 kJ. That means you get slightly over twice as many therms from burning methane as you do graphite for a given quantity of CO2 produced. So it’s no wonder that the switchover to natural gas has reduced CO2 emission so drastically!

An unregulated market is a double edged sword for your greenhouse gas policy, however. It’s just blind luck that a lower-carbon-footprint energy source became economical. The market can just as easily make natural gas less economical, or make a higher-carbon-footprint source (e.g., tar sands) economical.

27-May-2012

I observed the recent eclipse from a local park, where a bunch of people had gathered, and there was confusion about why the moon appeared on the lower side of the sun’s disk, rose over the course of the eclipse, and left off the top side, which was a west-to-east direction. (Here in North America, the sun was in the western sky for the eclipse. In Asia, the moon’s disk still moves west-to-east, but as it was in the eastern sky, that started above the sun and ended below.) This is due to a few astronomical facts: The earth’s rotation, the earth’s orbit, and the moon’s orbit are all around axes that point in roughly the same direction; the moon orbits the earth more frequently than the earth orbits the sun, the earth revolves even more frequently; and the moon’s shadow moves across the earth faster than the surface moves from the earth’s rotation. (An eclipse lasts shorter than a day, which is shorter than a month, which is shorter than a year.) Because the axes all roughly align, everything is moving in the same direction, west to east. Because we on the earth’s surface are moving west-to-east with the earth’s rotation, we see everything that revolves more slowly than the earth’s rotation as moving east-to-west in the sky. If the earth weren’t rotating, then we’d see the moon and sun move west to east in the sky, taking a month and year to complete their circuits. The disk of the moon moves through the sky over 12 times as fast as the disk of the sun, so relative to the sun we see it moving west to east.

At the park, I tried explaining this by pointing to the sky and moving my arms along west-east trajectories, but perhaps some diagrams will help. Looking down from above the north pole:
We see how the moon is moving west-to-east through space, but as the earth is rotating west-to-east with such a higher angular velocity, its disk moves east-to-west through our sky.

Now, when an eclipse happens, the moon’s shadow falls on the earth:
Because the moon only needs to pass through a tiny fraction of its orbit to sweep its shadow from one edge of the earth to the other, its shadow moves quicker than the earth’s rotation, so its west-to-east motion overtakes the earth’s surface’s, and we perceive the eclipse as starting to the west and moving east (in this case, starting in Asia and moving east over the North Pacific to North America).

At least that’s the normal case. These axes aren’t quite aligned: As the earth’s axis is tilted some 23 degrees, it’s possible for a polar eclipse to occur “north” of the north pole or “south” of the south pole:
Here the shadow is still moving “west” to “east”, as they would be defined by an observer away in space, but our reference for east and west is the earth’s 23-degree-tilted surface, so reversed, and we’d consider such an eclipse to be moving from east to west. Looking down from above the southern hemisphere:
Here we see that the moon is still moving west to east like always, and the shadow follows the moon, but because it passes over the south pole, it goes from moving with the earth’s rotation to against it, so we observe it moving east to west on the earth’s surface.

3-May-2007

Okay, so the Periodic Table of the Elements is one of the iconic symbols of Chemistry. Even if you flunked your high school Chem, you’ll recognize it instantly. Unfortunately, if you flunked high school Chem, you won’t actually know what it means.

Not recognizing that it’s a systematic arrangement of all the chemical elements, elucidating their properties in terms of their electron structure, you’re tempted to fill it in instead with items from whatever interest you do have. Make a Periodic Table of Fruit, or a Periodic Table of Government, or a Periodic Table of Rhetoric, then feel like you’ve somehow contributed something useful to Fruit classification. But what does this non-Elemental table mean? Do the properties of fruit recur periodically as something corresponding to atomic number increases? What even corresponds to atomic number? Why should fruit group as if it had electron shells? Does your table actually explain anything? Or are you just capitalizing on the fact that atoms do have electron shells and so elemental properties do arrange into a periodic table which is tremendously useful for chemistry, and applying it to something completely inappropriate?

20-Oct-2005

So, the results from the meta-meta-analysis (seriously) are in: Despite what well-selling relationship books may tell you, men and women are way more alike than different. Ha! I figured this was all over-exaggerated and over-weighted.